IPF and hypercarbic respiratory failure

Today in report at the VA, we heard about the case of an 86 yo man with IPF who presented for worsening dyspnea on exertion and a 30 pound weight loss over the course of several months who was found to be somnolent and hypercarbic requiring BiPap support and eventually was intubated for refractory hypercarbia.

We had several great PEARLS from report, but here are some highlights:

If someone looks uncomfortable on NIPPV, think about titrating the I:E time. For restrictive lung diseases, increasing the inspiratory time may be helpful, while for obstructive disease, an extended expiratory time may be required to help with vent synchrony.

While IPF usually presents with progressive hypoxia, hypercarbia can occur can occur in acute exacerbations (due to infections, heart failure, PE), but can also occur in late stage disease with increased dead-space and worsening lung compliance that makes air resistance so severe that the respiratory muscles can no longer sustain loads. A thorough search for reversible causes should be undertaken.

Patients who are intubated and have IPF have an extremely poor prognosis. One study showed 90% mortality at 2 months follow up.